I'm new to Linux, so I hope I'll be giving you helpful info here. On my last (recently deceased) laptop, I was running Ubuntu 14.04, and on that system my bluetooth Sony MDR-ZX770BT stereo headphones worked beautifully.
Now I have a brand new Lenovo G50-70 64-bit notebook with Ubuntu 16.04 preinstalled. The audio device is Haswell-ULT HD Audio Controller by Intel.
The headphones work now, but only in mono. When I look at sound settings, and check sound there, it tells me the sound is mono. Mono sound is coming through both sides of the headphone. I also think the built-in speakers are putting out mono, the sound is not good at all.
I've installed both blueman and pulseaudio controller. While pulseaudio will allow me to try both modes (headset and A2DP sink), blueman tells me that only headset mode will work, and the error message I get in blueman is "failed to change profile to a2dp_sink".
I've googled and checked here and can't find anything concerning this specific problem. It doesn't help that I'm ignorant of audio matters. I brought up alsamixer in the terminal, but don't understand what I'm looking at.
I'll be happy to post any logs once I know how to get to them.
Thank you in advance for any help you can give.